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Repeated connection drop, T3 time-outs

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Regular Visitor

Repeated connection drop, T3 time-outs

I’m a teacher trying to teach remotely, but my xfinity internet connection is extremely unreliable. Multiple times per hour it will drop the connection, kicking me off my webconference classroom. The modem’s event log shows repeated T3 time-outs and failed ranging attempts. It is especially bad during a rain storm, which happens every afternoon right now. I woke up this morning to no internet fifteen minutes before my class started, but it came back just in time after a power cycle reset.

Please help me. I don’t have time to sit on hold and go through the multiple levels of tech attempts when it seems obvious to me that the local node or the lines outside my house have a physical connection issue.

Thu Jul 30 05:20:35 2020 Critical (3) TFTP Request Retries exceeded, CM unable to register
Thu Jul 30 05:20:35 2020 Critical (3) TFTP failed - Request sent - No Response;CM-MAC=20:3d:66:17:2c:bf;CMTS-MAC=00:01:5c:71:4a:74;CM-QOS=1.1;CM-VER=3.0;
Thu Jul 30 05:16:53 2020 Critical (3) TLV-11 - Illegal Set operation failed;CM-MAC=20:3d:66:17:2c:bf;CMTS-MAC=00:01:5c:71:4a:74;CM-QOS=1.1;CM-VER=3.0;
Thu Jul 30 05:16:26 2020 Critical (3) No Ranging Response received - T3 time-out
Thu Jul 30 05:16:12 2020 Critical (3) TFTP Request Retries exceeded, CM unable to register
Thu Jul 30 05:16:12 2020 Critical (3) TFTP failed - Request sent - No Response;CM-MAC=20:3d:66:17:2c:bf;CMTS-MAC=00:01:5c:71:4a:74;CM-QOS=1.1;CM-VER=3.0;
Thu Jul 30 05:12:29 2020 Critical (3) TLV-11 - Illegal Set operation failed;CM-MAC=20:3d:66:17:2c:bf;CMTS-MAC=00:01:5c:71:4a:74;CM-QOS=1.1;CM-VER=3.0;
Thu Jul 30 05:12:01 2020 Critical (3) No Ranging Response received - T3 time-out
Thu Jul 30 05:11:46 2020 Critical (3) TFTP Request Retries exceeded, CM unable to register
Thu Jul 30 05:11:46 2020 Critical (3) TFTP failed - Request sent - No Response;CM-MAC=20:3d:66:17:2c:bf;CMTS-MAC=00:01:5c:71:4a:74;CM-QOS=1.1;CM-VER=3.0;
Thu Jul 30 05:08:03 2020 Critical (3) TLV-11 - Illegal Set operation failed;CM-MAC=20:3d:66:17:2c:bf;CMTS-MAC=00:01:5c:71:4a:74;CM-QOS=1.1;CM-VER=3.0;
Thu Jul 30 05:07:27 2020 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=20:3d:66:17:2c:bf;CMTS-MAC=00:01:5c:71:4a:74;CM-QOS=1.0;CM-VER=3.0;
Thu Jul 30 05:07:26 2020 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=20:3d:66:17:2c:bf;CMTS-MAC=00:01:5c:71:4a:74;CM-QOS=1.0;CM-VER=3.0;
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Expert

Re: Repeated connection drop, T3 time-outs

Please also post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.




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Regular Visitor

Re: Repeated connection drop, T3 time-outs

At this moment, Downstream power levels range from -11.6 to -15.2 dBmV, SNRs of 33.0 to 35.0.
Upstream is 45.2 to 50.5.

I have checked the connections in the attic and they are all tight and seem fine (not corroded or anything). Since the SNRs and transmission rates seem fine most of the time, I don’t believe the problem is from coax or connections in the house. It just intermittently loses signal, drops, and then reconnects after a few minutes.
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Expert

Re: Repeated connection drop, T3 time-outs

The stats are out of spec. See if anything below applies. If not, you'll need a tech out to investigate / correct the problem;

 

In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.

 

Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home.

 

 



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Diamond Problem Solver

Re: Repeated connection drop, T3 time-outs

Since the SNRs and transmission rates seem fine most of the time
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Adding to @EG, they are not fine, downstream and their SNRs are out of spec. What “connections” do you have in the attic or elsewhere (splitters etc). You can’t discount your house being the problem without a comparison of levels.

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Regular Visitor

Re: Repeated connection drop, T3 time-outs

There are no splitters, just a union between the cable from the street and the cable in the attic. That cable runs directly to the cable modem. Those connections on the union are tight and visually non-corroded. We use an antenna for TV, so we don’t split the cable line to the modem.
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Regular Visitor

Re: Repeated connection drop, T3 time-outs

How can I get a tech booked to visit my house?